#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>

int main(int argc, char *argv[])
{
	struct stat st;
	if (argc != 3) {
		fprintf(stderr, "Usage: <input filename> <output filename>\n");
		return -1;
	}
	if (stat(argv[1], &st) != 0) {
		fprintf(stderr, "Error opening file '%s': %s\n", argv[1],
			strerror(errno));
		return -1;
	}
	printf("'%s' size: %lld bytes\n", argv[1], (long long)st.st_size);
	if (st.st_size > 510) {
		fprintf(stderr, "%lld >> 510!!\n", (long long)st.st_size);
		return -1;
	}
	char buf[512];
	memset(buf, 0, sizeof(buf));
	FILE *ifp = fopen(argv[1], "rb");
	int size = fread(buf, 1, st.st_size, ifp);
	if (size != st.st_size) {
		fprintf(stderr, "read '%s' error, size is %d.\n", argv[1],
			size);
		return -1;
	}
	fclose(ifp);
	buf[510] = 0x55;
	buf[511] = 0xAA;
	FILE *ofp = fopen(argv[2], "wb+");
	size = fwrite(buf, 1, 512, ofp);
	if (size != 512) {
		fprintf(stderr, "write '%s' error, size is %d.\n", argv[2],
			size);
		return -1;
	}
	fclose(ofp);
	printf("build 512 bytes boot sector: '%s' success!\n", argv[2]);
	return 0;
}
